A paper round robin was conducted to evaluate the workability and reproducibility of a unified draft fracture toughness test standard titled “Standard Method for Measurement of Fracture Toughness.” The paper round robin consisted of 19 records from fracture toughness tests conducted separately from this round-robin exercise. These test records were given to the participants with the requirement that they use the draft standard to evaluate the fracture toughness values from the tests. The round robin was conducted between February 1991 and June 1992. Originally more than 30 organizations were invited to participate; however, only five finally responded with complete analyses of all of the test records. The five participants were all experienced in fracture testing and analyses. To subject the method to an evaluation by persons with less experience, some of the test records were analyzed by graduate students whose only experience with fracture testing and analyses was a course on fracture mechanics.

The round robin was conducted on Draft 10 of the proposed standard: “Standard Method for Measurement of Fracture Toughness” This paper contains a brief description of the draft test method, a discussion of the specimens and test records supplied, a brief summary of results, and a discussion of the changes made to the test method as a result of the round-robin exercise. All tests and analyses were conducted using English units; therefore, to accurately transmit the results, English rather than SI are used as the primary units of this report.